Field of the invention
The present invention relates to a securing structure of a stand for forming legs of a keyed instrument such as an electronic piano.
As shown in FIGS. 6 through 8, a stand of this type in the prior art has a pair of side plates 114 and 114 supporting a main body of the keyed instrument, and a back plate 115 secured between the side plates 114 and 114 and reinforcing them. A base 116 is secured to the bottom end of each side plate 114 and a pedal board 118 is arranged between the bases 116 and 116.
A securing structure shown in FIG. 6 uses round nuts 151. The round nuts 151 are inserted into a pair of apertures 152 and 152 formed in the rear face of the back plate 115. Screws 155 are passed through a pair of screw apertures 153 and 153 formed at the end face of the back plate 115 and through a pair of through apertures 154 and 154. The back plate 115 and the side plate 114 are secured together by the screws 155 and the round nuts 151.
Securing structures shown in FIGS. 7 and 8 each uses a L-shaped fitting 156. In the structure of FIG. 7, the back plate 115 and the side plate 114 are mutually secured by firstly securing one side of the L-shaped fitting 156 to the side plate 114 by screws, and then fastening screws 158 through apertures 157 formed in the back plate 115 into threaded apertures formed in the other side of the L-shaped fitting 156. On the other hand, in the structure of FIG. 8, the back plate 115 and the side plate 114 are mutually secured by firstly securing one side of the L-shaped fitting 156 to the back plate 115 by screws, and then fastening screws 160 through apertures 159 formed in the side plate 114 into threaded apertures formed in the other side of the L-shaped fitting 156.
However since both the securing structure of FIGS. 7 and 8 are so constructed that the back plate 115 is fastened through the L-shaped fitting 156 in a direction crossing a direction aproaching toward each other, there is formed with a gap between the side plate 114 and the back plate 115 which causes looseness therebetween, and accordingly it is impossible to firmly secure them together.
In the securing structure of FIG. 6, the back plate 115 is directly abutted against the side plate 114 and they are fastened toward each other and therefore the problems caused by the structures of FIGS. 7 and 8 are overcome. However since the round nuts 151 are liable to rotate or slide in longitudinal direction in their apertures 152, it is troublesome to align the through apertures 154 and the round nuts 151, and difficult to assemble them.